Moss Motors, Ltd

I got my distributor rebuilt by advanced distributor, however I can not get it to run well at all. distributor is in correctly, checked it 3 times now, base timing should be good enough to get it to run. And yet it will idle and backfire out the carbs constantly if you touch the throttle. Even with me advancing and retarded it I can get it to even backfire just idling aswell. I figured it was running lean right? nope added some more fuel and the car still backfires. I'm super confused on what is going on. Anyone care to lend some insight? Maybe I forgot to do something I don't know at this point.

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1954 MG TF 1250cc
Fully restored
She's a driver not a show car.

Is the firing order correct?

1-3-4-2 (firing order)

Also check point gap and try substituting a different condenser. I've seen this movie before. It once took me all day to detect a defective condenser. THAT won't happen again. Of course, if you've installed electronic ignition, I'd have to say, "Never mind."

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

My son's 1970's Cooper died all of a sudden. After checking everything, we found that the rotor had gone south. Check that too!

If Jeff replaced the rotor when he restored your distributor, I doubt that the rotor is the problem (he has about the only rotors that don't cause a problem).  That said, it wouldn't hurt to try a different rotor (purchase it from Jeff so you get one that will last).  If you are still running with points, then check the points gap AND try a new condenser.  New condensers usually fail in the first few hours of installation if they are going to fail at all.  Finally, you say that the distributor is in correctly - I am going to ask if you are certain that you got it in and set up with #1 cylinder at TDC on the compression stroke?  Remember that the mark on the crankshaft pulley will line up with the timing pointer when the #1 cylinder is TDC on the compression stroke AND with the #4 cylinder at TDC on the compression stroke.  Unless you checked which cylinder was on the compression stroke, you have a 50 - 50 chance of getting it wrong (or right).

 

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Cheers,
Dave
http://homepages.donobi.net/sufuelpumps/

I check the distributor again another 3 times and its in correctly. I have an electronic setup so no points or condenser here. He did tell me that unless it had resistor spark plugs this can cause problems with random missfires. I am running Autolite 63 plugs which they say is in the resistor class, yet they list it as supressor. Makes me wonder if I need a true Resistor plug. I think this might be my problem.

 

Well I talked to him and he recommended a different resistor plug to try out. So wish me luck! 

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1954 MG TF 1250cc
Fully restored
She's a driver not a show car.

Well swapped the plugs to ones with better resistance and it still misfires like crazy. I even added a few temporarry ground strapes to see if that would help and it didn't do anything.

 However I pulled the #4 plug out and laid it against some metal to see if it was getting spark and the car fired right up and even ran smoothly with that cylinder being dead. I then checked all 4 plugs for spark and they all have it. But when I put the plug back in it runs like scrap and misfires. I am thinking there is a ground issue with the ignition system. When I sent the distributor out it had that random ground strap that went under the cap. When I got it back it didn't have this anymore. I wonder if this is causing a problem. Though I did try clipping some grounds onto the distributor body to see if that was the problem and it didn't fix anything.  

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1954 MG TF 1250cc
Fully restored
She's a driver not a show car.

Spike, this sounds like cross firing due to high voltage breakdown either inside the cap or cross leads. With the plug out, the volage developed across the plug-gap [at atmospheric pressure] at spark over may be less than it would be with plug in [ at  high pressure??], maybe enough of a reduction to stop the breakdown?  Are you now using a new high-voltage coil?? Did you renew cap and leads or still using your originals? How clean the inside of the cap? Try starting up after dark and look for a fireworks display??

Hope you fix it     Cheers      steve

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To a man equipped with only a hammer, most problems look like nails

The only ignition upgrade for extra spark is the basic lucas sport "GOLD" coil. It does have a new cap,rotor,and modern style spark plug wires that fully cover the spark plug ends. I am really wondering if I need to make another ground strap that goes under the cap like the stock one did.

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1954 MG TF 1250cc
Fully restored
She's a driver not a show car.

At this point I would agree with Steve. Replace the cap rotor and wires. Make sure the correct wires are in the crrect towers on the cap for CCW rotation.  Also, I have had TWO Petronix igniton modules in my TD's  Mallory distributor. Both of them had fried within a years time. Lucky I keft the points with as a back-up. Jeff told me the Lucas Sport Coil did not have the required Ohms or Volts or whatever. I now have the Petronix coil sold by Jeff in my TD but no more Petronix moduals for me. I stuck the original distributor back in along with its "optical triggered" Crane (no longer in business ) as opposed to the Petronix "magneticly triggered" modual. I hope I have better luck with this one, otherwise it's back to points for me.

Dave

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53'TD, family owned since new
80'B

I owe Motorbill a big “thanks.”  I’ve spent the better part of the last two days trying to sort out the problems with the ignition on my TF. It was barely running—only 1 + 2 cylinders were firing. I tried everything: plugs, wires, points, carbs; nothing helped. Then I saw his post about trying a different condenser, as I started to undue the nuts that hold the low voltage wire and the condenser to the distributor, I noticed that the plate that the points and the condenser sit on was loose.  The two bolts that attach the plate to the distributor body had loosened up.  I don’t think I would ever have found that fault if it had not been for MB’s suggestion.

P.S.

Runs fine now!

MGAd,

I'm glad I pointed in the right direction. I'm just getting ready to go on my "summer" (slightly delayed) vacation after an extraordinarily intense thirty straight days of work to get three, count 'em three, fresh restorations finished and ready for a show. A '55 healey 100, a slightly modified '65 Triumph Herald, and a '61 bugeye with virtually every aftermarket and custom fabricated option you could imagine installed, including a supercharger and a five speed; but that's just the beginning! Anyhow, you've made my Friday. Any time I actually help, I get a charge. I guess that's why I participate on this wonderful, well mannered site. You see, I'm really just a praise junkie!

Have a great weekend,

Bill 

 

 

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Hey William, I hope you enjoy your vacation. A lot of us appreciate the time you take to give us shade tree machanics a helping hand. Keeping these great old cars rolling is important and worthwhile and you deserve much credit for helping us do just that.

 Hat's off to ya ! 

from poolboy, Basil and Bill

Sorry for the long wait to update. I added two new ground straps and check the distributor again. I was somehow off 3 teeth after checking it many times. I guess that's why sometimes you need to walk away and not think about it for awhile. Anyhow got the car running and its great. Fires right up and idles great and is a bit quicker now with the extra timing in the motor. Over all great mod and well worth the cheap cost.

 

How much advanced are you guys running with a stock cam and compression on 87? right now I have 14* advanced dialed in. I was going to try 15 or 16* and see if it pings or not. With the super low compression I am doing all I can to make it some what quicker lol. 

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1954 MG TF 1250cc
Fully restored
She's a driver not a show car.

Are you speaking of 14 degrees initial? I'd not go that far. These engines will tend to suffer in silence until almost at complete failure, and if you've seen the size of the rods and such, you surely don't want them to suffer much! Or, are you speaking of total advance, such as can be displayed on a dial type timing light?

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon